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Tran TT, Lee Y, Roy S, Tran TU, Kim Y, Taniguchi T, Watanabe K, Milošević MV, Lim SC, Chaves A, Jang JI, Kim J. Synergetic Enhancement of Quantum Yield and Exciton Lifetime of Monolayer WS 2 by Proximal Metal Plate and Negative Electric Bias. ACS Nano 2024; 18:220-228. [PMID: 38127273 DOI: 10.1021/acsnano.3c05667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The efficiency of light emission is a critical performance factor for monolayer transition metal dichalcogenides (1L-TMDs) for photonic applications. While various methods have been studied to compensate for lattice defects to improve the quantum yield (QY) of 1L-TMDs, exciton-exciton annihilation (EEA) is still a major nonradiative decay channel for excitons at high exciton densities. Here, we demonstrate that the combined use of a proximal Au plate and a negative electric gate bias (NEGB) for 1L-WS2 provides a dramatic enhancement of the exciton lifetime at high exciton densities with the corresponding QY enhanced by 30 times and the EEA rate constant decreased by 80 times. The suppression of EEA by NEGB is attributed to the reduction of the defect-assisted EEA process, which we also explain with our theoretical model. Our results provide a synergetic solution to cope with EEA to realize high-intensity 2D light emitters using TMDs.
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Affiliation(s)
- Trang Thu Tran
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yongjun Lee
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Shrawan Roy
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Thi Uyen Tran
- Department of Smart Fab. Technology, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Youngbum Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Milorad V Milošević
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
- Instituto de Física, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso 78060-900, Brazil
| | - Seong Chu Lim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Smart Fab. Technology, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Andrey Chaves
- Department of Physics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
- Departamento de Física, Universidade Federal do Ceará, Campus do Pici, C.P. 6030, 60455-900 Fortaleza, Ceará, Brazil
| | - Joon I Jang
- Department of Physics, Sogang University, Seoul 04107, Republic of Korea
| | - Jeongyong Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
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2
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Chan YH, Haber JB, Naik MH, Neaton JB, Qiu DY, da Jornada FH, Louie SG. Exciton Lifetime and Optical Line Width Profile via Exciton-Phonon Interactions: Theory and First-Principles Calculations for Monolayer MoS 2. Nano Lett 2023; 23:3971-3977. [PMID: 37071728 DOI: 10.1021/acs.nanolett.3c00732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Exciton dynamics dictates the evolution of photoexcited carriers in photovoltaic and optoelectronic devices. However, interpreting their experimental signatures is a challenging theoretical problem due to the presence of both electron-phonon and many-electron interactions. We develop and apply here a first-principles approach to exciton dynamics resulting from exciton-phonon coupling in monolayer MoS2 and reveal the highly selective nature of exciton-phonon coupling due to the internal spin structure of excitons, which leads to a surprisingly long lifetime of the lowest-energy bright A exciton. Moreover, we show that optical absorption processes rigorously require a second-order perturbation theory approach, with photon and phonon treated on an equal footing, as proposed by Toyozawa and Hopfield. Such a treatment, thus far neglected in first-principles studies, gives rise to off-diagonal exciton-phonon self-energy, which is critical for the description of dephasing mechanisms and yields exciton line widths in excellent agreement with experiment.
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Affiliation(s)
- Yang-Hao Chan
- Institute of Atomic and Molecular Sciences, Academia Sinica, and Physics Division, National Center of Theoretical Physics, Taipei 10617, Taiwan
- Department of Physics, University of California, Berkeley, California 94720-7300, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jonah B Haber
- Department of Physics, University of California, Berkeley, California 94720-7300, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Mit H Naik
- Department of Physics, University of California, Berkeley, California 94720-7300, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jeffrey B Neaton
- Department of Physics, University of California, Berkeley, California 94720-7300, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Kavli Energy NanoSciences Institute at Berkeley, University of California, Berkeley, California 94720, United States
| | - Diana Y Qiu
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, United States
| | - Felipe H da Jornada
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Steven G Louie
- Department of Physics, University of California, Berkeley, California 94720-7300, United States
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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3
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Heyn C, Ranasinghe L, Deneke K, Alshaikh A, Duque CA, Hansen W. Strong Electric Polarizability of Cone-Shell Quantum Structures for a Large Stark Shift, Tunable Long Exciton Lifetimes, and a Dot-to-Ring Transformation. Nanomaterials (Basel) 2023; 13:nano13050857. [PMID: 36903737 PMCID: PMC10004794 DOI: 10.3390/nano13050857] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 06/01/2023]
Abstract
Strain-free GaAs cone-shell quantum structures (CSQS) with widely tunable wave functions (WF) are fabricated using local droplet etching (LDE) during molecular beam epitaxy (MBE). During MBE, Al droplets are deposited on an AlGaAs surface, which then drill low-density (about 1 × 107 cm-2) nanoholes with adjustable shape and size. Subsequently, the holes are filled with GaAs to form CSQS, where the size can be adjusted by the amount of GaAs deposited for hole filling. An electric field is applied in growth direction to tune the WF in a CSQS. The resulting highly asymmetric exciton Stark shift is measured using micro-photoluminescence. Here, the unique shape of the CSQS allows a large charge-carrier separation and, thus, a strong Stark shift of up to more than 16 meV at a moderate field of 65 kV/cm. This corresponds to a very large polarizability of 8.6 × 10-6 eVkV -2 cm2. In combination with simulations of the exciton energy, the Stark shift data allow the determination of the CSQS size and shape. Simulations of the exciton-recombination lifetime predict an elongation up to factor of 69 for the present CSQSs, tunable by the electric field. In addition, the simulations indicate the field-induced transformation of the hole WF from a disk into a quantum ring with a tunable radius from about 10 nm up to 22.5 nm.
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Affiliation(s)
- Christian Heyn
- Center for Hybrid Nanostructures (CHyN), University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Leonardo Ranasinghe
- Center for Hybrid Nanostructures (CHyN), University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Kristian Deneke
- Center for Hybrid Nanostructures (CHyN), University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Ahmed Alshaikh
- Center for Hybrid Nanostructures (CHyN), University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Carlos A. Duque
- Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín AA 1226, Colombia
| | - Wolfgang Hansen
- Center for Hybrid Nanostructures (CHyN), University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
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4
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Suthar R, T A, Dahiya H, Singh AK, Sharma GD, Karak S. Role of Exciton Lifetime, Energetic Offsets, and Disorder in Voltage Loss of Bulk Heterojunction Organic Solar Cells. ACS Appl Mater Interfaces 2023; 15:3214-3223. [PMID: 36601721 DOI: 10.1021/acsami.2c18199] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Recently, the power conversion efficiency (PCE) of organic solar cells (OSCs) has significantly progressed with a rapid increase from 10 to 19% due to state-of-the-art research on nonfullerene acceptor molecules and various device processing strategies. However, OSCs still exhibit significant open circuit voltage loss (ΔVOC ∼ 0.6 V) due to high energetic offsets and molecular disorder. In this work, we present a systematic investigation to determine the effects of energetic offset and disorder on different recombination losses in open circuit voltage (VOC) using 13 different photoactive layers, wherein the PCE and ΔVOC vary in the ranges of 2.21-14.74% and 0.561-1.443 V, respectively. The detailed voltage loss analysis of all these devices was carried out, and voltage losses were correlated with energetic offset and disorder. This has enabled us to identify the key features for minimizing the voltage loss like: (1) a low energy offset between the donor and acceptor molecular states is essential to attain a nonradiative voltage loss (ΔVOC, nrad) as low as ∼200 meV and (2) Urbach energy, which is a measure of the materials' disorder and packing, should be low for the minimization of the radiative voltage loss (ΔVOC, rad). In addition, time-resolved photoluminescence spectroscopy was employed to further understand the exciton dynamics of pristine materials and donor-acceptor blends. It was observed that the absorbers with ultralong exciton lifetime (∼1000 ps) produce higher efficiencies. The current study emphasizes the importance of simultaneously testing photovoltaic performance and active layer exciton dynamics for rational device optimization and opens new prospects for designing novel molecules with fine-tuning of energetic offset and disorder with longer exciton lifetime which is the effective strategy to boost the efficiency of OSCs to their modified Shockley-Queisser (SQ) limit by minimizing radiative and nonradiative voltage losses.
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Affiliation(s)
- Rakesh Suthar
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi110016, India
| | - Abhijith T
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi110016, India
| | - Hemraj Dahiya
- Department of Physics, The LNM Institute of Information Technology, Jaipur, Rajasthan302031, India
| | - Abhishek Kumar Singh
- Department of Electronics Engineering, Rajiv Gandhi Institute of Petroleum Technology, Amethi, Uttar Pradesh229304, India
| | - Ganesh D Sharma
- Department of Physics, The LNM Institute of Information Technology, Jaipur, Rajasthan302031, India
| | - Supravat Karak
- Organic and Hybrid Electronic Device Laboratory, Department of Energy Science and Engineering, Indian Institute of Technology Delhi, New Delhi110016, India
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5
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Sharma A, Zhu Y, Halbich R, Sun X, Zhang L, Wang B, Lu Y. Engineering the Dynamics and Transport of Excitons, Trions, and Biexcitons in Monolayer WS 2. ACS Appl Mater Interfaces 2022; 14:41165-41177. [PMID: 36048513 DOI: 10.1021/acsami.2c08199] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The study of transport and diffusion dynamics of quasi-particles such as excitons, trions, and biexcitons in two-dimensional (2D) semiconductors has opened avenues for their application in high-speed excitonic and optoelectronic devices. However, long-range transport and fast diffusion of these quasi-particles have not been reported for 2D systems such as transition metal dichalcogenides (TMDCs). The reported diffusion coefficients from TMDCs are low, limiting their use in high-speed excitonic devices and other optoelectronic applications. Here, we report the highest exciton diffusion coefficient value in monolayer WS2 achieved via engineering the radiative lifetime and diffusion lengths using static back-gate voltage and substrate engineering. Electrostatic doping is observed to modulate the radiative lifetime and in turn the diffusion coefficient of excitons by ∼three times at room temperature. By combining electrostatic doping and substrate engineering, we push the diffusion coefficient to an extremely high value of 86.5 cm2/s, which has not been reported before in TMDCs and is even higher than the values in some 1D systems. At low temperatures, we further report the control of dynamic and spatial diffusion of excitons, trions, and biexcitons from WS2. The electrostatic control of dynamics and transport of these quasi-particles in monolayers establishes monolayer TMDCs as ideal candidates for high-speed excitonic circuits, optoelectronic, and photonic device applications.
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Affiliation(s)
- Ankur Sharma
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Yi Zhu
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
- Department of Engineering, University of Cambridge, Cambridge CB3 0FA, United Kingdom
| | - Robert Halbich
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Xueqian Sun
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Linglong Zhang
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Bowen Wang
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
| | - Yuerui Lu
- School of Engineering, College of Engineering and Computer Science, The Australian National University, Canberra, ACT 2601, Australia
- ARC Centre of Excellence in Quantum Computation and Communication Technology ANU Node, Canberra, ACT 2601, Australia
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6
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Morrell MV, Pickett A, Bhattacharya P, Guha S, Xing Y. Inorganic Ruddlesden-Popper Faults in Cesium Lead Bromide Perovskite Nanocrystals for Enhanced Optoelectronic Performance. ACS Appl Mater Interfaces 2021; 13:38579-38585. [PMID: 34358425 DOI: 10.1021/acsami.1c06350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
While the layered hybrid Ruddlesden-Popper (RP) halide perovskites have already established themselves as the frontrunners among the candidates in optoelectronics, their all-inorganic counterparts remain least explored in the RP-type perovskite family. Herein, we study and compare the optoelectronic properties of all-inorganic CsPbBr3 perovskite nanocrystals (PNCs) with and without RP planar faults. We find that the RP-CsPbBr3 PNCs possess both higher exciton binding energy and longer exciton lifetimes. The former is ascribed to a quantum confinement effect in the PNCs induced by the RP faults. The latter is attributed to a spatial electron-hole separation across the RP faults. A striking difference is found in the up-conversion photoluminescence response in the two types of CsPbBr3 PNCs. For the first time, all-inorganic RP-CsPbBr3 PNCs are tested in light-emitting devices and shown to significantly outperform the non-RP CsPbBr3 PNCs.
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Affiliation(s)
- Maria V Morrell
- Department of Biomedical, Biological & Chemical Engineering, University of Missouri, Columbia, Missouri 65211, United States
| | - Alec Pickett
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Payal Bhattacharya
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Suchismita Guha
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Yangchuan Xing
- Department of Biomedical, Biological & Chemical Engineering, University of Missouri, Columbia, Missouri 65211, United States
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7
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Guo C, Xu J, Ping Y. Substrate effect on excitonic shift and radiative lifetime of two-dimensional materials. J Phys Condens Matter 2021; 33:234001. [PMID: 33647889 DOI: 10.1088/1361-648x/abeacf] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
Substrates have strong effects on optoelectronic properties of two-dimensional (2D) materials, which have emerged as promising platforms for exotic physical phenomena and outstanding applications. To reliably interpret experimental results and predict such effects at 2D interfaces, theoretical methods accurately describing electron correlation and electron-hole interaction such as first-principles many-body perturbation theory are necessary. In our previous work (2020Phys. Rev. B102205113), we developed the reciprocal-space linear interpolation method that can take into account the effects of substrate screening for arbitrarily lattice-mismatched interfaces at the GW level of approximation. In this work, we apply this method to examine the substrate effect on excitonic excitation and recombination of 2D materials by solving the Bethe-Salpeter equation. We predict the nonrigid shift of 1s and 2s excitonic peaks due to substrate screening, in excellent agreements with experiments. We then reveal its underlying physical mechanism through 2D hydrogen model and the linear relation between quasiparticle gaps and exciton binding energies when varying the substrate screening. At the end, we calculate the exciton radiative lifetime of monolayer hexagonal boron nitride with various substrates at zero and room temperature, as well as the one of WS2where we obtain good agreement with experimental lifetime. Our work answers important questions of substrate effects on excitonic properties of 2D interfaces.
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Affiliation(s)
- Chunhao Guo
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, 95064, United States of America
| | - Junqing Xu
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, 95064, United States of America
| | - Yuan Ping
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, 95064, United States of America
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8
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Anantharaman SB, Kohlbrecher J, Rainò G, Yakunin S, Stöferle T, Patel J, Kovalenko M, Mahrt RF, Nüesch FA, Heier J. Enhanced Room-Temperature Photoluminescence Quantum Yield in Morphology Controlled J-Aggregates. Adv Sci (Weinh) 2021; 8:1903080. [PMID: 33643780 PMCID: PMC7887577 DOI: 10.1002/advs.201903080] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/04/2020] [Indexed: 05/12/2023]
Abstract
Supramolecular assemblies from organic dyes forming J-aggregates are known to exhibit narrowband photoluminescence with full-width at half maximum of ≈9 nm (260 cm-1). Applications of these high color purity emitters, however, are hampered by the rather low photoluminescence quantum yields reported for cyanine J-aggregates, even when formed in solution. Here, it is demonstrated that cyanine J-aggregates can reach an order of magnitude higher photoluminescence quantum yield (increase from 5% to 60%) in blend solutions of water and alkylamines at room temperature. By means of time-resolved photoluminescence studies, an increase in the exciton lifetime as a result of the suppression of non-radiative processes is shown. Small-angle neutron scattering studies suggest a necessary condition for the formation of such highly emissive J-aggregates: the presence of a sharp water/amine interface for J-aggregate assembly and the coexistence of nanoscale-sized water and amine domains to restrict the J-aggregate size and solubilize monomers, respectively.
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Affiliation(s)
- Surendra B. Anantharaman
- Laboratory for Functional PolymersEmpaSwiss Federal Laboratories for Materials Science and TechnologyÜberlandstrasse 129DübendorfCH‐8600Switzerland
- Institut des MatériauxÉcole Polytechnique Fédérale de LausanneEPFL Station 12LausanneCH‐1015Switzerland
- Present address:
Department of Electrical and Systems EngineeringUniversity of PennsylvaniaSäumerstrasse 4, RüschlikonPhiladelphiaPA19104USA
| | - Joachim Kohlbrecher
- Laboratory for Neutron Scattering and Imaging (LNS)Paul Scherrer InstituteVilligenCH‐5232Switzerland
| | - Gabriele Rainò
- Laboratory of Inorganic ChemistryDepartment of Chemistry and Applied BiosciencesETH ZürichVladimir Prelog‐Weg 1ZürichCH‐8093Switzerland
- Laboratory for Thin Films and PhotovoltaicsEmpaSwiss Federal Laboratories of Materials Science and TechnologyÜberlandstrasse 129, DübendorfZürichCH‐8600Switzerland
| | - Sergii Yakunin
- Laboratory of Inorganic ChemistryDepartment of Chemistry and Applied BiosciencesETH ZürichVladimir Prelog‐Weg 1ZürichCH‐8093Switzerland
- Laboratory for Thin Films and PhotovoltaicsEmpaSwiss Federal Laboratories of Materials Science and TechnologyÜberlandstrasse 129, DübendorfZürichCH‐8600Switzerland
| | - Thilo Stöferle
- IBM Research–ZurichSäumerstrasse 4, RüschlikonZürichCH‐8803Switzerland
| | - Jay Patel
- Laboratory for Functional PolymersEmpaSwiss Federal Laboratories for Materials Science and TechnologyÜberlandstrasse 129DübendorfCH‐8600Switzerland
| | - Maksym Kovalenko
- Laboratory of Inorganic ChemistryDepartment of Chemistry and Applied BiosciencesETH ZürichVladimir Prelog‐Weg 1ZürichCH‐8093Switzerland
- Laboratory for Thin Films and PhotovoltaicsEmpaSwiss Federal Laboratories of Materials Science and TechnologyÜberlandstrasse 129, DübendorfZürichCH‐8600Switzerland
| | - Rainer F. Mahrt
- IBM Research–ZurichSäumerstrasse 4, RüschlikonZürichCH‐8803Switzerland
| | - Frank A. Nüesch
- Laboratory for Functional PolymersEmpaSwiss Federal Laboratories for Materials Science and TechnologyÜberlandstrasse 129DübendorfCH‐8600Switzerland
- Institut des MatériauxÉcole Polytechnique Fédérale de LausanneEPFL Station 12LausanneCH‐1015Switzerland
| | - Jakob Heier
- Laboratory for Functional PolymersEmpaSwiss Federal Laboratories for Materials Science and TechnologyÜberlandstrasse 129DübendorfCH‐8600Switzerland
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9
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Li Z, Lu X, Cordovilla Leon DF, Lyu Z, Xie H, Hou J, Lu Y, Guo X, Kaczmarek A, Taniguchi T, Watanabe K, Zhao L, Yang L, Deotare PB. Interlayer Exciton Transport in MoSe 2/WSe 2 Heterostructures. ACS Nano 2021; 15:1539-1547. [PMID: 33417424 DOI: 10.1021/acsnano.0c08981] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A moiré superlattice formed by stacking two lattice mismatched transition metal dichalcogenide monolayers, functions as a diffusion barrier that affects the energy transport and dynamics of interlayer excitons (electron and hole spatially concentrated in different monolayers). In this work, we experimentally quantify the diffusion barrier experienced by interlayer excitons in hexagonal boron nitride-encapsulated molybdenum diselenide/tungsten diselenide (MoSe2/WSe2) heterostructures with different twist angles. We observe the localization of interlayer excitons at low temperature and the temperature-activated diffusivity as a function of twist angle and hence attribute it to the deep periodic potentials arising from the moiré superlattice. We further support the observations with theoretical calculations, Monte Carlo simulations, and a three-level model that represents the exciton dynamics at various temperatures.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Ibaraki 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
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10
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May MA, Jiang T, Du C, Park KD, Xu X, Belyanin A, Raschke MB. Nanocavity Clock Spectroscopy: Resolving Competing Exciton Dynamics in WSe 2/MoSe 2 Heterobilayers. Nano Lett 2021; 21:522-528. [PMID: 33301334 DOI: 10.1021/acs.nanolett.0c03979] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Transition-metal dichalcogenide heterostructures are an emergent platform for novel many-body states from exciton condensates to nanolasers. However, their exciton dynamics are difficult to disentangle due to multiple competing processes with time scales varying over many orders of magnitude. Using a configurable nano-optical cavity based on a plasmonic scanning probe tip, the radiative (rad) and nonradiative (nrad) relaxation of intra- and interlayer excitons is controlled. Tuning their relative rates in a WSe2/MoSe2 heterobilayer over 6 orders of magnitude in tip-enhanced photoluminescence spectroscopy reveals a cavity-induced crossover from nonradiative quenching to Purcell-enhanced radiation. Rate equation modeling with the interlayer charge transfer time as a reference clock allows for a comprehensive determination from the long interlayer exciton (IX) radiative lifetime τIXrad = (94 ± 27) ns to the 5 orders of magnitude faster competing nonradiative lifetime τIXnrad = (0.6 ± 0.2) ps. This approach of nanocavity clock spectroscopy is generally applicable to a wide range of excitonic systems with competing decay pathways.
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Affiliation(s)
- Molly A May
- Department of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder 80309, Colorado, United States
| | - Tao Jiang
- Department of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder 80309, Colorado, United States
- MOE Key Laboratory of Advanced Micro-Structured Materials, and School of Physics Science and Engineering, Tongji University, Shanghai 200092, China
| | - Chenfeng Du
- Department of Physics, University of Washington, Seattle 98195, Washington, United States
| | - Kyoung-Duck Park
- Department of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder 80309, Colorado, United States
- Department of Physics, School of Natural Sciences, Ulsan National Institute of Science and Technology, Ulsan, South Korea
| | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle 98195, Washington, United States
| | - Alexey Belyanin
- Department of Physics and Astronomy, Texas A&M University, College Station 77843, Texas, United States
| | - Markus B Raschke
- Department of Physics, Department of Chemistry, and JILA, University of Colorado, Boulder 80309, Colorado, United States
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11
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Wang L, Cai X, Li B, Li M, Wang Z, Gan L, Qiao Z, Xie W, Liang Q, Zheng N, Liu K, Su SJ. Achieving Enhanced Thermally Activated Delayed Fluorescence Rates and Shortened Exciton Lifetimes by Constructing Intramolecular Hydrogen Bonding Channels. ACS Appl Mater Interfaces 2019; 11:45999-46007. [PMID: 31718132 DOI: 10.1021/acsami.9b16073] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A fast radiative rate, highly suppressed nonradiation, and a short exciton lifetime are key elements for achieving efficient thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) with reduced efficiency roll-off at a high current density. Herein, four representative TADF emitters are designed and synthesized based on the combination of benzophenone (BP) or 3-benzoylpyridine (BPy3) acceptors, with dendritic 3,3″,6,6″-tetra-tert-butyl-9'H-9,3':6',9″-tercarbazole (CDTC) or 10H-spiro(acridine-9,9'-thioxanthene) (TXDMAc) donors, respectively. Density functional theory simulation and X-ray diffraction analysis validated the formation of CH···N intramolecular hydrogen bonds regarding the BPy3-CDTC and BPy3-TXDMAc compounds. Notably, the construction of intramolecular hydrogen bonding within TADF emitters significantly enhances the intramolecular charge transfer (ICT) strength while reducing the donor-acceptor (D-A) dihedral angle, resulting in accelerated radiative and suppressed nonradiative processes. With short TADF exciton lifetimes (τTADF) and high photoluminescence quantum yields (ϕPL), OLEDs employing BPy3-CDTC and BPy3-TXDMAc dopants realized maximum external quantum efficiencies (EQEs) up to 18.9 and 25.6%, respectively. Moreover, the nondoped device based on BPy3-TXDMAc exhibited a maximum EQE of 18.7%, accompanied by an extremely small efficiency loss of only 4.1% at the luminance of 1000 cd m-2. In particular, the operational lifetime of the sky-blue BPy3-CDTC-based device was greatly extended by 10 times in contrast to the BP-CDTC-based counterpart, verifying the idea that the in-built intramolecular hydrogen bonding strategy was promising for the realization of efficient and stable TADF-OLEDs.
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Affiliation(s)
- Liangying Wang
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices , South China University of Technology , Wushan Road 381 , Guangzhou 510640 , P. R. China
| | - Xinyi Cai
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices , South China University of Technology , Wushan Road 381 , Guangzhou 510640 , P. R. China
| | - BinBin Li
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices , South China University of Technology , Wushan Road 381 , Guangzhou 510640 , P. R. China
| | - Mengke Li
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices , South China University of Technology , Wushan Road 381 , Guangzhou 510640 , P. R. China
| | - Zhiheng Wang
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices , South China University of Technology , Wushan Road 381 , Guangzhou 510640 , P. R. China
| | - Lin Gan
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices , South China University of Technology , Wushan Road 381 , Guangzhou 510640 , P. R. China
| | - Zhenyang Qiao
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices , South China University of Technology , Wushan Road 381 , Guangzhou 510640 , P. R. China
| | - Wentao Xie
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices , South China University of Technology , Wushan Road 381 , Guangzhou 510640 , P. R. China
| | - Qiumin Liang
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices , South China University of Technology , Wushan Road 381 , Guangzhou 510640 , P. R. China
| | - Nan Zheng
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices , South China University of Technology , Wushan Road 381 , Guangzhou 510640 , P. R. China
| | - Kunkun Liu
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices , South China University of Technology , Wushan Road 381 , Guangzhou 510640 , P. R. China
| | - Shi-Jian Su
- State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices , South China University of Technology , Wushan Road 381 , Guangzhou 510640 , P. R. China
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12
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Jin Y, Zhang Y, Liu Y, Xue J, Li W, Qiao J, Zhang F. Limitations and Perspectives on Triplet-Material-Based Organic Photovoltaic Devices. Adv Mater 2019; 31:e1900690. [PMID: 30957919 DOI: 10.1002/adma.201900690] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 02/27/2019] [Indexed: 06/09/2023]
Abstract
Organic photovoltaic cells (OPVs) have attracted broad attention and become a very energetic field after the emergence of nonfullerene acceptors. Long-lifetime triplet excitons are expected to be good candidates for efficiently harvesting a photocurrent. Parallel with the development of OPVs based on singlet materials (S-OPVs), the potential of triplet materials as photoactive layers has been explored. However, so far, OPVs employing triplet materials in a bulk heterojunction have not exhibited better performance than S-OPVs. Here, the recent progress of representative OPVs based on triplet materials (T-OPVs) is briefly summarized. Based on that, the performance limitations of T-OPVs are analyzed. The shortage of desired triplet materials with favorable optoelectronic properties for OPVs, the tradeoff between long lifetime and high binding energy of triplet excitons, as well as the low charge mobility in most triplet materials are crucial issues restraining the efficiencies of T-OPVs. To overcome these limitations, first, novel materials with desired optoelectronic properties are urgently demanded; second, systematic investigation on the contribution and dynamics of triplet excitons in T-OPVs is necessary; third, close multidisciplinary collaboration is required, as proved by the development of S-OPVs.
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Affiliation(s)
- Yingzhi Jin
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, SE-581 83, Sweden
| | - Yanxin Zhang
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Yanfeng Liu
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, SE-581 83, Sweden
| | - Jie Xue
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Weiwei Li
- State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Juan Qiao
- Key Lab of Organic Optoelectronics and Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, 100084, P. R. China
| | - Fengling Zhang
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, SE-581 83, Sweden
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13
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Miller B, Steinhoff A, Pano B, Klein J, Jahnke F, Holleitner A, Wurstbauer U. Long-Lived Direct and Indirect Interlayer Excitons in van der Waals Heterostructures. Nano Lett 2017; 17:5229-5237. [PMID: 28742367 DOI: 10.1021/acs.nanolett.7b01304] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We report the observation of a doublet structure in the low-temperature photoluminescence of interlayer excitons in heterostructures consisting of monolayer MoSe2 and WSe2. Both peaks exhibit long photoluminescence lifetimes of several tens of nanoseconds up to 100 ns verifying the interlayer nature of the excitons. The energy and line width of both peaks show unusual temperature and power dependences. While the low-energy peak dominates the spectra at low power and low temperatures, the high-energy peak dominates for high power and temperature. We explain the findings by two kinds of interlayer excitons being either indirect or quasi-direct in reciprocal space. Our results provide fundamental insights into long-lived interlayer states in van der Waals heterostructures with possible bosonic many-body interactions.
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Affiliation(s)
- Bastian Miller
- Walter Schottky Institut and Physics-Department, Technical University of Munich , Am Coulombwall 4a, 85748 Garching, Germany
- Nanosystems Initiative Munich (NIM) , Schellingstrasse 4, 80799 München, Germany
| | - Alexander Steinhoff
- Institut für Theoretische Physik, Universität Bremen , P.O. Box 330 440, 28334 Bremen, Germany
| | - Borja Pano
- Walter Schottky Institut and Physics-Department, Technical University of Munich , Am Coulombwall 4a, 85748 Garching, Germany
| | - Julian Klein
- Walter Schottky Institut and Physics-Department, Technical University of Munich , Am Coulombwall 4a, 85748 Garching, Germany
- Nanosystems Initiative Munich (NIM) , Schellingstrasse 4, 80799 München, Germany
| | - Frank Jahnke
- Institut für Theoretische Physik, Universität Bremen , P.O. Box 330 440, 28334 Bremen, Germany
| | - Alexander Holleitner
- Walter Schottky Institut and Physics-Department, Technical University of Munich , Am Coulombwall 4a, 85748 Garching, Germany
- Nanosystems Initiative Munich (NIM) , Schellingstrasse 4, 80799 München, Germany
| | - Ursula Wurstbauer
- Walter Schottky Institut and Physics-Department, Technical University of Munich , Am Coulombwall 4a, 85748 Garching, Germany
- Nanosystems Initiative Munich (NIM) , Schellingstrasse 4, 80799 München, Germany
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Younts R, Duan HS, Gautam B, Saparov B, Liu J, Mongin C, Castellano FN, Mitzi DB, Gundogdu K. Efficient Generation of Long-Lived Triplet Excitons in 2D Hybrid Perovskite. Adv Mater 2017; 29:1604278. [PMID: 28009459 DOI: 10.1002/adma.201604278] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/13/2016] [Indexed: 06/06/2023]
Abstract
Triplet excitons form in quasi-2D hybrid inorganic-organic perovskites and diffuse over 100 nm before radiating with >11% photoluminescence quantum efficiency (PLQE) at low temperatures.
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Affiliation(s)
- Robert Younts
- Department of Physics, North Carolina State University, Raleigh, NC, 27695-8202, USA
| | - Hsin-Sheng Duan
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708-0300, USA
| | - Bhoj Gautam
- Department of Physics, North Carolina State University, Raleigh, NC, 27695-8202, USA
| | - Bayrammurad Saparov
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708-0300, USA
| | - Jie Liu
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708-0300, USA
| | - Cedric Mongin
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - David B Mitzi
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC, 27708-0300, USA
| | - Kenan Gundogdu
- Department of Physics, North Carolina State University, Raleigh, NC, 27695-8202, USA
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